Method of fabricating prismatic yarn and the resulting product



April 5, 1966 w G. SCHARF 3,244,544

METHOD OF FAB RICATING PRISMATIC YARN AND THE RESULTING PRODUCT Original Filed Sept. 28, 1962 2 Sheets-Sheet 1 m 4 Ec 4 8 Z E6 0 v d a Z 0 g 3 @Q- Q [\J 9&-

rl INVENTOR.

MCw GSUMQF ATrOFW y April 5, 1966 w. e. SCHARF METHOD OF FABRICATING PRISMATIC YARN AND THE RESULTING PRODUCT Original Filed Sept. 28, 1962 wta @EQOO INVENTOR. M4069 G SCH 419i kz W030 988% 2 Sheets-Sheet 2 United States Patent 3 244 544 METHUD 0F FABRiATilNG PRHSMATIC YARN AND THE RESULTING PRODUCT Walter G. Scharf, 243 Palmer Court, Ridgewood, NJ. Continuation of applications, Ser. No. 153,892, Nov. 21,

1961, and Ser. No. 226,919, Sept. 28, 1962. This application Apr. 8, 1965, Ser. No. 446,580

8 Claims. (Cl. 1174) This application is a continuation of my copending application Serial No. 226,919, filed September 28, 1962, combined with my copending application Serial No. 153,892, filed November 21, 1961, both of which are now abandoned.

This invention relates generally to synthetic yarns suitable for textiles and the like, and more particularly to prismatic yarns having a brillant, rainbow lined appearance as well as to metallized yarns which exhibit glowing or iridescent color effects of varying shade and hue.

Color adds much to the interest and attractiveness of textile yarns. As is known from wave theory, what the eye perceives as color is really a particular wavelength of radiation in the visible spectrum. Thus to impart color to yarn, the usual practice is to introduce dyes or pigments which absorb or subtract out certain wavelengths from white light and reflect the rest.

For example, while a yarn may appear red when exposed to white light because its pigment absorbs the other colors, in a red light it will seem pale and white, for it then reflects nearly all the light falling upon it. But when placed under a green light it will appear almost black since a red yarn will absorb green light. It will be evident therefore that color is not an inherent quality of a material but rather represents the absorption or reflection characteristics of the material to light of a particular kind.

Another way of creating color is by means of light dis persion, that is by passing white light (sunlight) through a retracting medium which separates and spreads the color components of the light. Thus a prism will disperse white light into the spectrum of a rainbow. In this instance color is produced not by selective absorption, as with pigment, but by light dispersion.

Accordingly, it is the primary object of this invention to provide a yarn presenting a brilliant, rainbow-hued prismatic appearance.

A significant feature of the yarn of the invention is that when the yarn is knitted or woven into a fabric, the fabric appears to glitter and to possess gem-like chromatic qualities unattainable with conventional yarns.

In US. Patent No. 2,974,055, there is disclosed a nonlaminated, filamentary metallized thread which is produced by vacuum plating a relatively broad web of thermoplastic material, such as Mylar, with a metal deposit of aluminum or other metal. The metal deposit is thereafter coated with a transparent plastic in liquid form which is then cured to form a film which adheres directly thereon. The plastic-coated metallized web is slit to form filamentary threads. Such threads, being produced entirely without adhesive, are not subject to delamination and have a good hand as well as high tensile strength.

The color of non-laminated threads of the above described type is determined by the natural brilliance of the metal deposit as seen through a transparent coating. Other color effects may be produced by introducing pigment or dyestuff in the coating, in which event the color of the metal is optically combined with that in the coating to produce chromatic hues. But in either case, since both the metal layer and the coating thereon are highly "ice uniform in thickness, the resultant color is also of consistent uniformity in its shading or saturation, and therefore somewhat lacking in sparkle.

Accordingly, it is also an object of this invention to provide a non-laminated, metallized yarn producing glowing or iridescent color effects which are highly attractive.

Also an object of the invention is to provide a metallized non-laminated yarn in which the yarn is not only multi-colored in appearance, but the respective colors are in turn constituted by varying shades. As a consequence, when the yarn is woven or otherwise formed into fabric, the fabric appears to have myriad colors of extraordinary brilliance, with color effects which sparkle and vary as the fabric moves under the light.

For a better understanding of the invention, as well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein:

FIG. 1 is a schematic diagram of a system for carrying out the technique in accordance with the invention;

FIG. 2 is a perspective view of the disturber roll incorporated in the system shown in FIG. 1;

FIG. 3 is a cross section of the prismatic yarn produced by the system;

FIG. 4 is a fabric woven of prismatic yarn;

FIG. 5 is a schematic diagram showing the first stage in one preferred process in accordance with the invention;

FIG. 6 is a schematic diagram showing the second stage of the process;

FIG. 7 illustrates in perspective the disturber roll used in the second stage;

FIG. 8 is a section taken through a yarn produced by the process;

FIG. 9 schematically shows the process for producing multiple color effects; and

FIG. 10 is a perspective view of the multi-color web produced by the process in FIG. 9.

Referring now to the drawing and more particularly to FIG. 1, in a system for producing prismatic yarn, a web 10 is provided which is drawn from a supply roll, the web being constituted by a transparent synthetic material such as cellophane, acetate, tri-acetate, acetate butyrate or polymerized ethylene glycol terephthalate (Mylar) or any other suitable transparent and flexible material capable of acting as a yarn. The thickness of the web for yarn should ordinarily not exceed 2 mils, but of course other thicknesses may be used, if desired.

The web 10 is then coated on one side with a clear resin in solution, the resin chosen being compatible with the base web. Among the useable resins are polyester resins, acrylic and epoxy resins and nitrocellulose resins. Polyester resins, for example, are soluble in ketones or other organics and when cured provide a transparent film of good mechanical strength. Epoxy resins exhibit exceptionally good adhesion to a wide variety of materials, their physical characteristics being similar to polyesters. For use with Mylar, the solutions disclosed in Patent 2,979,055 may be used.

The coating is applied uniformly by means of a three roller coater 11, including a tank 12 for containing the resin solution, a first roller being rotatable in the bath and acting to apply the liquid to a second roller 13 which engages the underside of web 10, the web being pressed against the second roller by means of a third roller 14.

It is important that the coating be non-porous extremely thin, almost of molecular thickness and for this purpose the solution should be exceptionally dilute. Thus 'in preparing the solution the ratio of resin solids, which may be in powder or flake form, to the solvent should be from 1 to by weight, and preferably in the order of 2%. While a three roll coater is disclosed, it is to be understood that the coating may be applied by a roller coater, a reverse roller coater or by the fiexographic or rotogravure process.

The wet coating emerging from the coater 11 is then disturbed, while still wet, by a disturber rod or roll 15 which act in conjunction with a roll 16 to upset the uniformity of the coating in a random manner and to reform the coating into an uneven hill and dale area.

This is accomplished, as shown separately in FIG. 2, by the use of a motor drive system which not only rotates the disturber roll 15 but also causes it to reciprocate laterally with respect to the advancing web 10. Helically wound about the rod and secured thereto is a wire 21. In practice, roll 15 may take the form of a rod of 1% inches in diameter, having a fine steel wire helically wound thereabout, the wire being of a diameter of to of an inch thick or even finer. The reciprocation of the rod is also made non-uniform so that the coating is built up in certain areas and diminished in others to provide a microscopically roughened surface.

The wet and disturbed coating on web 10 is then dried and cured by passing the web through an oven 17 which is properly heated and vented to drive off all solvents and at the same time to effect the curing of the coating material. For heating purposes, steam, gas heat or infra-red radiation may be employed, as desired. The temperature of the oven and the travel time therethrough are determined by the specific web and coating materials. The coating may be further cured by cooling drums 18 disposed at the exit end of the oven. Cooling may be accomplished by a circulating water system or a refrigerant.

The web coated on one side is rolled up on reel 19, and the identical coating process is repeated for the other side of the web. Thereafter the web coated on both sides may be slit or severed into flat threads in accordance with the usual practice in the art. Standard widths run in the order of to $5 of an inch.

Thus the yarn, as shown sectionally in FIG. 3, is formed by a transparent base 22 having clear coatings 22a and 22b on either side thereof, the coatings being highly uneven. Light passing through this combination will be refracted and dispersed to produce prismatic effects which endow the yarn with the hues of the rainbow and impart a high brilliance and sheen thereto. The dimensions in FIG. 3 are, of course, exaggerated.

In practice the yarn, as shown in FIG. 4, may be woven to form a fabric constituted by warp threads 23 and woof threads 24, each thread being formed by a supporting yarn 25 of a conventional form in combination with prismatic yarns 26. This supported composite makes possible other color effects, in that by providing a colored support filament, say in black, this color affords a ground to set off the rainbow etfect produced by the prismatic yarn. Thus the color of the support filament acts to emphasize one of the colors and the net effect is a fabric having a basic coloration determined by the color of the support filaments, which basic coloration is enlivened by the rainbow effects of the prismatic yarns.

A metal coating or foil may be interposed between the resin coating and the base web whereby prismatic effects will be obtained not by light passing through the yarn but light reflected from the metal coating. It is also to be understood that a prismatic yarn may be produced by coating only one side of the base web rather than both sides. To obtain the uneven coating, means other than a disturber rod may be used. For example, by advancing the web immediately after coating up an inclined plane, the web coating will tend to run downwardly in a counterdirection and thereby build up a hill and dale effect providing the desired result.

As shown in FIG. 5, in the first stage of a process in accordance with the invention for producing a glowingly colored metallized thread, a continuous web of transparent thermoplastic material is drawn from a supply roll 111 and is caused to travel through a high vacuum chamber 112 in which one surface of the film is metallized. The web may be constituted of cellophane, acetate, tri-acetate, acetate butyrate, polymerized ethylene glycol terephthal ate (Mylar), or any other suitable transparent and flexible material capable of being vacuum plated. The thickness of the web for ordinary yarn does not exceed 2 mils, but of course other thicknesses may be used in other applications.

in the vacuum chamber, one surface 110a of the web 110 is metal-plated by gold, silver, aluminum, magnesium, titanium, nickel or any other metal, the thickness of the metal layer preferably not exceeding $3 of an inch, The deposition may be carried out by known thermal evaporation or cathodic sputtering techniques. In thermal evaporation, metal vapor is generated by direct heat such as an electric arc source or a glowing filament. T 0 effect maximum adherence of the plated film, the metal atoms should pass linearly from their source to the surface to be coated and this requires the maintenance of pressures of about l0 inches of mercury in the vacuum chamber. In cathode sputtering, a high voltage is impressed between an anode and a cathode of the plating metal. The cathode is vaporized by a positive-ion bombardment, some of the vapor diffusing away from the cathode and depositing on the web to be plated. The voltage requirements depend on the nature of the cathode metal. At pressures of 0.01 to 0.10 mm. of mercury necessary to maintain the glow discharge, the ordinary laws of diffusion prevail. After plating the web is re-rolled in preparation for the next step.

In the second stage shown in FIG. 6, to produce a yarn having the desired color properties, the metallized web is then uniformly coated on the metallized side 110a with a clear resin in solution, the resin chosen being compatible with the base web. Among the useable resins are polyester resins, acrylic and epoxy resins and nitrocellulose resins. Modified vinyl or modified nitrocellulose coatings may also be used. Polyester resins, for example, are soluble in organic solvents, such as ethylene dichloride or dioxane, and When cured provide a transparent film of good mechanical strength. Epoxy resins exhibit exceptionally good adhesion to a wide variety of materials, their physical characteristics being similar to polyesters.

Color is added to the resinous solution by means of pigments or dyes to form in effect a printing ink. When dried or cured, the ink forms a colored, transparent coating which adheres to the metal deposit on the base web. Preferably dyestuff is used, such as Acetosol dyes manufactured by the Sandoz Company, Orasol made by Ciba, or Grasol made by Geigy.

In actual practice, I have prepared a coating solution for a Mylar base by dissolving a copolymer of poly-ethylene terephthalate and polyethylene isophthalate, available commercially as Vitel PElOO (Goodyear) in dioxane (diethylene dioxide), available commercially as Dioxane- 1,4 (Union Carbide). The ratio by weight of the powder to the solvent is 3 /2%. To this solution is added dye material, which in one example is Grasol Yellow 36 manufactured by Geigy. Since the coating is very thin, a large amount of dye must be used, and in practice one half pound of dye is used for five pounds of solvent.

The coating is applied uniformly by means of a threeroller coater generally designated by the numeral 113, including a tank 114 for containing the resin solution, the first roller 115 being rotatable in the bath and acting to apply the liquid to a second roller 116 which engages the metallized underside of web 110, the web being pressed against the second roller by means of a third roller 117.

It is important that the dried coating be extremely thin, and for this purpose the solution should be exceptionally dilute. Thus in preparing the solution the ratio of resin solids, which may be in powder or flake form, to the solvent, should be from 1.0% to 10% by weight,

and preferably in the order of 2%. While a three-roll coater is disclosed, it is to be understood that the coating may be applied by a roller coater, a reverse roller coater or by the fiexographic or rotogravure process, or any coating process capable of handling the coating viscosities required for satisfactory execution.

The Wet coating emerging from the coater 113 is then disturbed, while still wet, by a disturber rod or roll 118 which acts in conjunction With a roll 119 to upset the uniformity of the coating in a random manner to reform the coating into uneven hill-and-dale areas.

This is accomplished, as shown separately in FIG. 7, by the use of a motor drive system 120 which not only rotates the disturber roll 118 but also causes it to reciprocate laterally with respect to the advancing web 110. In practice, disturber roll 118 may take the form of a rod of 1% inches in diameter, having a fine steel wire helically wound thereabout, the wire being of a diameter of A to of an inch thick or even finer. Alternatively, the rod may be formed of steel having a helical groove 121 machined therein. The reciprocation of the rod is also made non-uniform so that the coating is built up in certain areas and diminished in others to provide a microscopically roughened surface.

The wet and disturbed coating on web 110 is then dried and cured by passing the web through an oven 122 which is properly heated and vented to drive off all solvents and at the same time to effect the drying or curing of the coating material. For heating purposes, any convection, conduction or radiant heat source may be employed, as determined by the coating characteristics. The temperature of the oven and the travel time therethrough are determined by the specific web and coating materials. The coating may be further cured by cooling drums 123 disposed at the exit end of the oven. Cooling may be accomplished by a circulating water system or a refrigerant.

Thereafter the coated and metallized web may be slit or severed into fiat threads by rotary knives 124 in accordance with the usual practice in the art. Standard widths run in the order of to M of an inch.

Thus the yarn, as shown sectionally in FIG. 8, is formed by a transparent base having a metal deposit 110a thereon which is covered by a colored plastic film 1100, the film being highly uneven. Light passing through this combination will be reflected by the metal deposit and refracted and dispersed by the colored film to produce prismatic effects which endow the yarn with iridescent colors and impart a high brilliance and sheen thereto. The dimensions in FIG. 8 are, of course, exaggerated. The basic colors of the yarn will constitute a ground for the iridescence. It is to be understood that the coating and plating may be applied to both sides of web 110, rather than merely to one side thereof.

In practice, the yarn may be woven to form a fabric constituted by warp threads and woof threads, each thread being formed by a supporting yarn of a conventional form in combination with the iridescent yarns. This sup ported composite makes possible still other color effects, in that by providing a colored support filament, say in black, this color aifords a background to set off the effect produced by the iridescent yarn. Thus the color of the support filament may act to emphasize one of the yarn colors.

The same basic process may be used to produce multicolor threads. As shown in FIG. 9, the metallized web 110 resulting from the process shown in FIG. 5, may be passed through a rotogravure press, generally designated by the numeral 125, wherein the metallized side 110a is printed by cylinders with color bands or stripes to be later described, the pr nting ink being of the same composition disclosed in connection with FIG. 6. Gravure printing is a process in which the image areas of a printing cylinder are recessed. The surface is first covered with ink and the excess is wiped off, leaving ink only for the recessed image, the image being transferred by pressure to the surface being printed.

The gravure printing unit 125 comprises a printing pressure cylinder 126 and an inking system including a fountain 127 whose ink is applied to cylinder 126 by an ink roll 128. The excess is removed by a doctor blade 129 and returned to the fountain. The pressure cylinders are covered with a resilient rubber composition that presses the web surface in contact with the ink in the tiny cells of the printing surface. The drawing, for simplicity, shows only a single gravure unit for a single color. In multi-color printing, two or more units operate in tandem and each color must be dried before the next is printed. The metallized web therefore is passed while wet through the disturber rolls 118 and 119 where the resinous layers printed on the Web are rendered uneven, and then through oven 122, after each impression. The rotogravure process as it relates to the application of the resinous printing ink is conventional and standard equipment, and may be used for this purpose.

In order to generate random color effects rather than uniform patterns, the rotogravure cylinders are provided with uneven bands or stripes of printing surface, which are askew relative to the cylinder axis. The printing is carried out so that, as shown in FIG. 10, a first color band A is laid down repetitively along the Web, which color band is rendered of uneven thickness, and a second color band B is laid down and disturbed to overlap partially or fall over the first band to produce an intermediate band C composed of the A and B combination, and so on. There is, of course, no limit to the number of colors which may be laid down by this process.

The printing is not limited to bars or stripes, and other geometric forms may be used. The printing may be carried out on both sides of the web, with the colors relatively displaced to further vary the random coloration.

Thus the color effects produced by the process may be Variegated both in hue, as by choice of printing inks, and in shade or saturation, as by the change in thickness of the layer. The color and shade variations, combined with the reflective characteristics of the metal deposit and the natural color thereof, as well as the prismatic effect produced by varying the thickness of the plastic layer, are so compounded optically as to create unusual and highly pleasing iridescent effects never before encountered in yarn design. Unusual effects may also be obtained in a yarn in which the metal deposit is omitted and the colored plastic film laid down directly on the web.

The brilliance of the yarns may be further enhanced by passing the coated and dried web through embossing rolls before the Web is slit to yarn size. For this purpose, conventional embossing rolls may be used in combination with a soft rubber or matted back-up roller to introduce further irregularities in the surface. Such embossing also acts to modify the gloss of the coated web and to create further variations in the total effect.

While there has been shown what are considered to be preferred embodiments of the invention, it will be manifest that many changes and modifications may be made therein without departing from the essential spirit of the invention. It is intended, therefore, in the annexed claims to cover all such changes and modifications as fall Within the true scope of the invention.

What I claim is:

1. The method of fabricating a prismatic yarn comprising the steps of:

(a) roller coating a web of thin transparent flexible synthetic material with a coating material consisting essentially of a highly dilute solution of transparent resin to produce an extremely thin uniform wet coating on said web,

(b) disturbing the thickness of said wet coating in a random manner,

(c) evaporating the solvent in said disturbed wet coating to produce a film on said web having random I areas of varying thickness producing iridescent effects, and

(d) slitting the coated web to yarn size.

2. The method as set forth in claim 1, wherein the ratio of the resin solids to the solvent in said solution is about 2%.

3. The method as set forth in claim 1, wherein said web is formed of polymerized ethylene glycol terephthalate.

4. The method, as set forth in claim 1, wherein said 10 web is formed of acetate butyrate.

5. The method, as set forth in claim 1, wherein said web is formed of acetate.

6. The method, as set forth in claim 1, wherein said Web is coated with a deposit of metallic material before it is roller coated with said resin.

7. A prismatic yarn made in accordance with the method set forth in claim 1.

method set forth in claim 6,

1,283,851 11/1918 Mayer 118-33 1,607,540 11/1926 Jonsson 117-10 1,755,818 4/1930 Ganzinotti 117-169 1,922,548 8/1933 Mattin 117-159 2,419,922 4/ 1947 Tippetts 1 17-7 2,464,453 3 1949 Linquist 11744 2,712,190 7/1955 Sobel 117-159 2,770,518 11/1956 Conciaton et a1. 117-138.8 2,819,179 1/1958 Bernard et a1 117-10 2,862,284 12/ 1958 Wiczer 260-25 2,874,674 2/1959 Hornbostel 118-113 2,875,087 2/1959 Crandon 117-10 2,957,780 10/1960 Stephens et a1 117-10 2,974,055 3/1961 Scharf 117-4 3,014,301 12/1951 Grupe 117-138.8

0 WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner. 

1. THE METHOD OF FABRICATING A PRISMATIC YARN COMPRISING THE STEPS OF: (A) ROLLER COATING A WEB OF THIN TRANSPARENT FLEXIBLE SYNTHETIC MATERIAL WITH A COATING MATERIAL CONSISTING ESSENTIALLY OF A HIGHLY DILUTE SOLUTION OF TRANSPARENT RESIN TO PRODUCE AN EXTREMELY THIN UNIFORM WET COATING ON SAID WEB, (B) DISTURBING THE THICKNESS OF SAID WET COATING IN A RANDOM MANNER, (C) EVAPORATING THE SOLVENT IN SAID DISTURBED WET COATING TO PRODUCE A FILM ON SAID WEB HAVING RANDOM AREAS OF VARYING THICKNESS PRODUCING IRIDESCENT EFFECTS, AND (D) SLITTING THE COATED WEB TO YARN SIZE. 